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991.
992.
Li Jing Li Pei Qian Zhou Xudong Hu Song Gao Chunhui Qi Xiaodong Wen Nan Jia 《Optics Communications》2011,284(13):3428-3432
This paper investigates two key techniques used in 60 GHz Radio over Fiber (RoF) technology for wireless access, namely, the generation of 60 GHz signals and the distribution of 60 GHz local oscillator (LO). In the proposed model, a 60 GHz PSK signal is generated by a heterodyne of two subcarriers with narrow-angle PSK (NA-PSK) modulation, whose phase shift is equal to one half that of a normal PSK signal. Then we use a 60 GHz mixer to frequency mix two PSK signals in two different bands, 60 GHz and baseband. By doing this, the modulation information can be fully eliminated, resulting in a 60 GHz LO. In the wireless terminal, coherent demodulation is realized by a self-mixing of the transmitted 60 GHz PSK signal and LO. Thus no millimeter-wave (mm-wave) band oscillator is needed in the wireless terminal. 相似文献
993.
H. Qi D.L. Wang L.M. Ruan 《Journal of Quantitative Spectroscopy & Radiative Transfer》2011,112(15):2507-2519
Particle Swarm Optimization (PSO) algorithms, including standard PSO, Stochastic PSO, and Multi-Phase PSO, are applied to solve the time-domain inverse transient radiation problems in the present research. Time-resolved transmittance and reflectance signals of four different measuring models serve as the measurement data, which estimate absorption, scattering coefficients, and geometric position within one-dimensional non-homogeneous media by inverse simulation. To check retrieval performances and accuracies of PSO-based approaches, four different inverse transient radiation cases are investigated to deal with one homogeneous layer, two-layer, three-layer, and continuous non-homogenous media. The influences of different searching ranges, swarm sizes, and maximum fly velocities on the fitness function of PSO are discussed. Meanwhile, the effects of measurement errors on the reconstruction accuracy are also investigated. All the results confirm that radiative parameters could be estimated accurately with measurement noise using PSO-based approaches. 相似文献
994.
The effect of delay, nonlinearity and noise on oscillatory motion is of permanent interest for theoretical and experimental research. Here we explore a negative feedback loop between p53 and Mdm2 with a time delay, which is a key circuit in the response of cells to damage. This circuit shows noisy sustained oscillations in individual human cells following DNA damage, and damped oscillations at the cell population level. We demonstrate the effect of delay on the oscillation, and the correlation in time course. In a multi-species system, the events at different time points which span a time delay are coupled even when the delay is large compared with the other characteristic times of the system. We also clarify that the dynamics at the single-cell level appears to be coherent resonance, and the origin of the damped oscillation at the macroscopic level out of the sustained ones at the single-cell level can be ascribed to the dephasing process which is induced by the interplay between nonlinearity and noise. The findings are consistent with experimental observations and advance our understanding of the dynamics of the p53 network. 相似文献
995.
We present a spatial-domain fiber cavity ring-down (CRD) technique that does not require optical pulses for time-resolved detection. Instead of measuring the intensity decay rate of an optical pulse in the time domain as in conventional CRD experiments, we measure the decay rate of a CW signal in a ring-down cavity (RDC) using frequency-shifted interferometry in the spatial domain, as a function of distance traveled by the light. As a proof-of-concept demonstration, we measured fiber bend loss in a loop RDC using this technique, and a cavity loss change as low as 0.0135 dB induced by every fiber turn on a mandrel was unambiguously discerned. 相似文献
996.
ZHAO Chuan SUN Sheng-Sen LI Cheng ZHANG Xiao-Jie HE Kang-Lin AN Qi CHEN Hong-Fang DAI Hong-Liang FENG Chang-Qing HENG Yue-Kun HUANG Ya-Qi HUANG Yan-Ping GUO Jian-Hua LI Wei-Dong LI Xiu-Rong LIU Fang LIU Huai-Min LIU Shu-Bin LIU Shu-Dong LIU Yong MA Xiang MAO Ze-Pu SHAO Ming SUN Yong-Jie SUN Zhi-Jia WU Jin-Jie YANG Gui-An ZHAO Lei ZHU Xing-Wang ZUO Jia-Xu 《中国物理C(英文版)》2011,35(1):72-78
The time calibration for end cap TOF system of BESⅢ is studied in this paper.It has achieved about 110 ps time resolution for muons in dimu events.The pulse height correction using electronic scan curve and the predicted time calculated using Kalman filter method are introduced.This paper also describes the study of using electrons and muous as calibration samples. 相似文献
997.
Propagation of optical vortex solitons due to the Gouy phase in strongly nonlocal nonlinear media 下载免费PDF全文
In this paper,we present a study on the propagation of the symmetrical optical vortices formed by two collinear Laguerre-Gauss solitons in strongly nonlocal nonlinear media.The optical vortices,which move along the beam axis as the light propagates,result in a rotation of the beam’s transverse profile.This physical reason of the rotation is the Gouy phase acquired by the component beams. 相似文献
998.
The morphology and ultrastructure of the alimentary canal in the adult female of the Japanese wax scale, Ceroplastes japonicus Green (Hemiptera: Coccoidea: Coccidae), was investigated using light microscopy, scanning electron microscopy and transmission electron microscopy. The results showed that the foregut was subdivided into a sclerotized pharynx and an oesophagus. A pair of salivary glands attached in the middle of the foregut. The loop-shaped midgut was narrow and longer than the foregut and its inner wall lined with a thick layer of epithelia. The hindgut was divided into a narrower ileum and a broader rectum, with the well-developed filter chamber enclosed in the anterior rectum. Malpighian tubules consisted of two brownish-yellow moniliform tubules with pores, approximately 1 μm in diameter, scattered on the outer surface and many spherical crystals inside the tubules. 相似文献
999.
通过荧光光谱法研究了5种轴向核苷(胞苷、氮杂胞苷、甲基胞苷、尿苷和甲基尿苷)衍生物修饰硅酞菁与牛血清白蛋白(BSA)的相互作用,结果表明,它们与BSA存在较强的相互作用,结合常数在(4.90~83.18)×105 mol-1·L之间。因此,进一步制备了二[5’-(2’,3’-O-异丙基)-胞苷氧基]硅酞菁(SiPc1)与BSA的非共价复合物(SiPc1-BSA),复合物中两者的摩尔比为1∶1。SiPc1-BSA与SiPc1在可见区的吸收光谱没有明显区别,两者的Q带最大吸收带均位于686nm附近,且吸收强度没有明显区别,这说明SiPc1结合到白蛋白后,其光谱性质没有受到明显改变。光动力抗癌活性测试表明,SiPc1-BSA具有较高的光动力抗癌活性,对人肝癌细胞HepG2的IC50值为3.0×10-7 mol·L-1,且SiPc1-BSA的光动力活性高于SiPc1(PBS药剂形式,IC50值为7.0×10-7 mol·L-1),这主要可归因于SiPc1-BSA具有更高癌细胞摄取率。 相似文献
1000.
We implement a two-atom √swap Bate via cavity QED. During the preparation, a cavity-assisted collision betweenatoms is required, and this does not need any auxiliary atom. The cavity is only virtually excited, thus our scheme is insensitive to the cavity field states and to the cavity decay. The scheme can be implemented by the present cavity QED techniques. 相似文献